In the first round, right after the bell, Foster is going to start jabbing and he will it Tua with a couple of good ones. At that point two things will happen. - Foster will think "this guy is easy to hit, I'm going to put something on him" and he will crank off a left hook. -Tua will not be hurt but he will notice that Foster has some snap to his jab. Tua will crank off a left hook too. They will exchange hooks and Tua will win the exchange and the fight.
Don't left hook with David Tua. Also don't get in the ring with him as a light heavyweight. It's a very bad for your health
Tua literally decapitates Foster with the first left hook he lands. And yes, I know the meaning of 'literally'.
It might go 2 or 3 rounds if Tua is really sloppy. But most likely it's a 1 round fight, maybe a 30 second job (including an unncessary ten-count).
Yeah, Tua is terrible style for Foster. That wouldn't last long, 3 rounds at most. I'd pick quite a few LHW over Tua, but definitely not Foster.